Effects of high-fat diet-induced obesity on metabolism and sexual development of juvenile male rats

Effects of high-fat diet-induced obesity on metabolism and sexual development of juvenile male rats | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effects of high-fat diet-induced obesity on metabolism and sexual development of juvenile male rats Shujuan Guo, Guimei Li, Juan Zheng This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5302221/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective To explore the effects of high-fat diet-induced obesity on the metabolism and sexual development of juvenile male rats. Methods Three-week-old male rats were divided into the control group and the model group. The two groups were fed normal and high-fat diets, respectively, for four weeks. Modeling was successful if Lee’s index exceeded the upper limit of Lee’s index of the control group. Levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT), aspartate transaminase (AST), testosterone (T), estrogen (E2), and insulin-like growth factor 1 (IGF-1) of the rats were monitored. Morphological structures of hepatic and testicular tissues were examined by hematoxylin and eosin (H&E) staining; hepatic steatosis was investigated by Oil Red O staining; and aromatases were detected using the immunohistochemical method. Results Weight, waist-to-height ratio, Lee’s index, weight and thickness of visceral fat, levels of ALT, AST, TC, TG, LDL-C, E2, and IGF-1 of rats were significantly higher in the model group than in the control group ( P < 0.05). H&E staining revealed that rats in the model group had hepatic steatosis, a disorder of seminiferous tubules, and a reduced quantity of spermatogenic cells. Oil Red O staining revealed a significantly increased accumulation of lipid droplets in hepatic cells. Immunohistochemical analysis revealed that aromatases in hepatic and testicular cells were up-regulated. Conclusion A high-fat diet induces dyslipidemia, thereby causing hepatic steatosis and liver dysfunction, and it significantly influences testicular development, as an increased level of aromatase leads to a reduced T level. high-fat diet lipid metabolism liver testis sex hormones Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction Childhood obesity has become a global epidemic [ 1 ] . Its occurrence is influenced by several factors, among which changes in dietary structure, such as high-fat diets, greatly increase the risk of obesity. A high-fat diet increases the accumulation of lipids, inducing hyperlipidemia. Hyperlipidemia plays an essential role in metabolic diseases, leading to hepatic steatosis, Type 2 diabetes, and atherosclerosis [ 2 ] . It also affects the functions of the hypothalamo-pituitary-gonadal axis, such as reducing testosterone (T) levels and increasing the risk of functional hypogonadism [ 3 , 4 ] . The influence of obesity on the reproductive system of male adults has been widely studied. However, some childhood obesity may persist into adulthood. Therefore, adult obesity is closely related to pubertal obesity, further highlighting the importance of studying the impact of pubertal obesity on the body. The correlation between boy obesity and the onset of adolescence in boys remains controversial. A multicenter epidemiological survey in China analyzed 9812 6-18-year-old boys and found that obesity was significantly positively correlated with sexual maturity [ 5 ] , consistent with other previous studies [ 6 ] . Crocker et al. reported a negative correlation between the degree of obesity in boys and testicular volume and pubic hair development. This might be related to the increased expression of aromatase in adipose tissue, promoting the conversion of T to estrogen (E2) and the occurrence of insulin resistance [ 7 ] . Oehme et al. conducted cross-sectional studies and found that boys with low body mass index (BMI) exhibited delayed sexual development, while boys with high BMI had similar sexual development time as boys with normal weight [ 8 ] . The inconsistency in these studies may be related to differences in the selection of indicators or the study population. Herein, a pubertal obesity rat model was constructed by administering a high-fat diet before sexual maturation to explore the effects of obesity on metabolism and sexual development. 2. Materials and methods 2.1 Materials twenty-two specific-pathogen-free Sprague Dawley (SD) male rats (3 weeks old, weighing 50–55 g) were maintained at a room temperature of 23–25℃ and on a 12/12-h light/dark cycle, with ad libitum access to drinking water and food. 2.2 Grouping and feeding The rats were randomly divided into the normal diet group and the high-fat diet group. The normal diet group received a regular diet as the control group (11 rats). The high-fat diet group received a high-fat and high-calorie diet as the model group (11 rats). All rats were raised until 7 weeks of age. 2.3 Indicators Food and water were withdrawn 6 h before measurement. Body length (distance from nose tip to anus), BMI, waist circumference, penis length, and testicular size were measured. Lee’s index was calculated as follows: Lee’s index = ( \(\:\sqrt[3]{\text{w}\text{e}\text{i}\text{g}\text{h}\text{t}\:}\times\:1000\) /body length (cm)) [ 9 ] . Criteria for successful modeling: Lee’s index of the model rat exceeded the upper limit of Lee’s index of the control group (mean ± standard deviation). 2.4 Reagents (1) Polyformaldehyde (Shanghai Sangon, China); (2) phosphate-buffered saline (PBS) powder (Zhongshan, China); (3) absolute alcohol (Sinopharm, China); (4) hematoxylin stain (Nanjing Jiangcheng, China); (5) eosin solution (Beyotime, China); (6) neutral resin (Sinopharm, China); (7) primary cytochrome P450 antibody (rabbit-derived) (Zen-bioscience, China); and (8) horseradish peroxidase-labeled secondary antibody (goat anti-rabbit) (Abcam, USA). 2.5 Methods After anesthetizing rats with 7% chloral hydrate (0.5 mL/100 g), approximately 10 mL of blood was collected from the abdominal aorta and transferred to a pro-coagulant tube. The blood was left to settle for 2 h and then the serum was stored at -20℃. The levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT), aspartate transaminase (AST), T, E2, and insulin-like growth factor 1 (IGF-1) were detected. After blood collection, hepatic and testicular tissues were collected separately, and residual blood was washed with PBS. Samples were fixed with 4% paraformaldehyde for hematoxylin and eosin (H&E) staining and immunohistochemical detection. Some hepatic tissues were made into frozen sections and used for Oil Red O staining to observe hepatic steatosis. Tissues were dehydrated, cleared, embedded in paraffin, and sliced (thickness = 5 µm). Sections were deparaffinized for further H&E staining. Morphological changes of the liver and testicles were observed under an optical microscope. Sections were dewaxed, antigen retrieved, blocked with goat serum, and incubated with a primary aromatase antibody (dilution ratio = 1:100) at 4℃ overnight. Sections were incubated with a goat anti-rabbit secondary antibody (dilution ratio = 1:50) at 37℃ for 30 min. After color development with diaminobenzidine, sections were counterstained with hematoxylin for 5 min, and expression changes of aromatase were observed under an optical microscope. Pale yellow indicates positive expression.The degree of hepatic steatosis was observed after staining, counterstaining and sealing of frozen sections, and the lipid droplets were orange. 2.6 Statistical analysis Statistical analysis was performed using SPSS 23.0 software, and data were expressed as mean ± SD. Two independent sample t-tests were used to compare normally distributed data, and a non-parametric test was used for comparison of non-normally distributed data. P < 0.05 was considered statistically significant and P < 0.01 was considered highly statistically significant. 3. Results 3.1 Analysis of body surface indicators Rats were raised to 7 weeks of age for comparative analysis. The results showed that the weight, waist-to-height ratio and Lee’s index were significantly higher and penis length was significantly lower in the model group than in the control group ( P 0.05). 3.2 Measurement of the fat pad and testicle Three rats were randomly selected from each group for fat pad and testicular measurements. The results showed that visceral fat weight, fat thickness of epididymis, perirenal area, and the greater omentum were significantly increased in the model group had compared with the control group, with statistically significant differences ( P 0.05). 3.3 Serum biochemical indicators ALT, AST, TC, TG, LDL-C, E2, and IGF-1 levels increased significantly and HDL-C and T levels decreased drastically in the model group compared with the control group, with statistically significant differences ( P < 0.05). 3.4 H&E staining of liver cells and testicles Liver cells had normal morphology and regular arrangement, and the nucleus was located in the center of the cell in control group rats. However, liver cells showed fat vacuoles that squeezed the nucleus in model group rats, resulting in varying degrees of steatosis. Additionally, the control group exhibited a regular arrangement of spermatogenic cells at all levels in the seminiferous tubules, with a complete and clear structure. However, intercellular connections in the upper layer of the seminiferous tubules were loose and the number of spermatogenic cells decreased in the model group. 3.5 Oil Red O staining of liver cells The cytoplasm of liver cells appeared light blue, and the nucleus appeared dark blue in the control group, with a small amount of lipid droplets (red particulates). The model group showed a significant increase in lipid droplets in liver cells, with a red cytoplasm. 3.6 Immunohistochemical detection of aromatases in hepatic and testicular tissues Accumulative and average optical densities of aromatases increased significantly in the hepatic cells of rats in the model group compared with those in the control group, with statistically significant differences ( P < 0.05). Moreover, accumulative and average optical densities of aromatases increased markedly in the testicular cells of rats in the model group compared with those in the control group, with statistically significant differences ( P < 0.05). 4. Discussion After excessive intake of high-calorie foods, adipocytes store excess glucose and fat as TGs [ 10 ] , with limitation. After reaching a critical level, the body will contribute to fat production by increasing the number of adipocytes [ 11 ] . Hyperplasia of abdominal adipose tissues leads to abdominal obesity due to high-fat production activity in the mesenteric adipose tissues [ 12 ] . At the end of feeding, Lee’s index increased significantly in the model group compared with the control group, and the total fat content in the epididymis, perirenal area, and greater omentum was significantly higher in the model group than in the control group, confirming the above viewpoint. The waist-to-height ratio, an important index to evaluate abdominal obesity [ 13 ] , provided guiding significance in predicting risk factors for cardiovascular diseases [ 14 ] . Clinically, hypertriglyceridemia, low HDL-C, and high LDL-C, termed “atherogenic lipid triad” [ 15 ] , have been considered the main risk factors for cardiovascular diseases. Our data demonstrated that the waist-to-height ratio increased significantly in the model group compared with the control group. Moreover, TC, TG, and LDL-C levels were significantly higher and the HDL-C level was lower in the model group than in the control group, consistent with the research results of obesity-induced dyslipidemia in humans [ 16 ] . Under a high-fat diet, adipocytes continuously break down to produce a large amount of free fatty acids and enhance the activity of lipoprotein lipase, leading to dyslipidemia and non-alcoholic fatty liver diseases [ 17 ] . Meanwhile, H&E staining revealed that the arrangement of liver cells in the model group was disordered during this period, with some rats developing steatosis. Oil Red O staining showed a significant increase in lipid droplets in liver cells. Lipid metabolism disorder and the increased synthesis and decreased oxidation of free fatty acids led to the accumulation of lipids and lipoproteins in cells, causing liver cell dysfunction [ 18 ] . Additionally, ALT and AST levels were significantly higher in the model group than in the control group. Currently, there is no uniform conclusion on the relationship between obesity and the onset of sexual development in boys. Lee et al. found that obese boys had delayed adolescence compared with normal and overweight boys based on a large-scale American population (3872 boys) [ 19 ] . Holmgren et al. defined adolescent development as the increase in height during adolescence and found that the adolescence of overweight and obese boys started 2.5–3.5 months earlier than normal-weight children [ 20 ] . A different study reported that obese children had increased insulin sensitivity and levels of gonadotropins (follicle-stimulating hormone and luteinizing hormone (LH)) and sex hormone-binding globulin (SHBG) after weight loss, suggesting that obesity had negative influences on the sexual development of boys [ 21 ] . The present study found that prepubertal obesity first affected the penis length of rats, which was significantly shorter than that of the control group. Although status changes in testicular tissues were observed under light microscopy, testicular volume and mass were not significantly affected. Excess accumulation of adipose tissues in the body enhanced aromatase activity, promoting the conversion of T into E2 [ 22 ] . Increased E2 levels further inhibited the function of the hypothalamus (gonadotropin-releasing hormone)-pituitary (LH)-testicular (Leydig cells) axis. Moreover, E2 can further reduce T synthesis by inhibiting 17a-hydroxylase activity [ 23 ] . Additionally, obesity can lead to insulin resistance, and insulin can inhibit the production of androgen and increase its clearance rate in the liver [ 24 ] , resulting in decreased serum levels of T. The current study found that the level of aromatase in the liver and testicular tissues increased in the model group compared with the control group. In addition, the level of E2 increased significantly and that of T decreased substantially in the model group compared with the control group, ultimately affecting the development of the penis. IGF-1, a polypeptide hormone composed of 70 amino acids, is mainly produced in the liver. It is also stimulated by growth hormones and insulin endocrine in the liver [ 25 ] . IGF-1 is closely related to various metabolic diseases, including obesity, Type 2 diabetes, and cardiovascular diseases [ 26 , 27 ] . Our study showed that the level of IGF-1 was significantly higher in the model than in the control group, which is related to the regulation of the stability and biological activity of IGF-1 by insulin-like growth factor binding protein-1 (IGFBP-1) produced by the liver and insulin regulation. Adipose tissue, an endocrine organ, is closely related to insulin sensitivity. The accumulation of visceral fat leads to increased production of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-alpha, and IL-8, which reduces insulin sensitivity and results in hyperinsulinemia and even insulin resistance [ 28 ] . However, we did not detect the insulin level but we speculate that insulin levels in the model group are elevated. Hyperinsulinemia not only reduces IGFBP-1 levels [ 29 ] but also directly stimulates the production of IGF-1. Low levels of IGFBP-1 can promote IGF-1 activity [ 30 ] , ultimately leading to increased IGF-1 secretion. Elevated IGF-1 levels also indicate the occurrence of metabolic disorders in rats. In summary, the sexual maturation of SD rats is approximately 6–10 weeks after birth [ 31 ] . We constructed a pubertal rat model of high-fat diet-induced obesity (7 weeks) to investigate the effects of prepubertal obesity on metabolism and sexual development. The findings demonstrated that a high-fat diet led to obesity, and the dyslipidemia induced by obesity not only affected the metabolic function of the liver but also damaged the reproductive system of male rats. Therefore, for children with prepubertal obesity, early dietary and weight management is essential to avoid the consequences of obesity. Declarations Ethics approval and consent to participate This study was approved by the Ethics Committee of Liaocheng People’s Hospital. Consent for publication All authors approved the final manuscript and the submission to this journal. Competing interests The authors declare no competing interests. Funding No funding was supported in this study. Author Contribution Conceptualization: Guimei Li.Data curation: Shujuan Guo.Formal analysis:Juan Zheng.Investigation: Shujuan Guo.Methodology:Juan Zheng.Project administration: Juan Zheng.Resources: Guimei Li.Software: Shujuan Guo.Supervision: Guimei Li.Validation: Juan Zheng.Visualization: Shujuan Guo.Writing – original draft: Shujuan Guo.Writing – review & editing: Juan Zheng.All authors reviewed the manuscript. Acknowledgments We would like to thank the study participants for their time. 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Tables Table 1 Comparison of physical parameters of model and control rats Model rats (n = 11) Control rats (n = 11) P-value Body weight (g) 193.96 ± 18.07 177.78 ± 11.91 0.022 * W/H 0.77 ± 0.03 0.62 ± 0.03 < 0.001 * Lee’s index 312.73 ± 5.20 280.87 ± 5.40 < 0.001 * Penis length (mm) 9.09 ± 0.39 11.06 ± 1.10 < 0.001 * Testicular volume (cm 3 ) 1.86 ± 0.24 2.10 ± 0.34 0.075 *: P < 0.05 W/H: ratio of waist circumference to body length Table 2 Comparison of visceral fat and testis of model and control rats Model rats (n = 3) Control rats (n = 3) P-value Visceral fat (g) 7.85 ± 0.89 4.95 ± 1.05 0.022 * Testicular weight (g) 1.22 ± 0.08 1.11 ± 0.52 0.105 Epididymal fat (mm) 4.38 ± 0.44 3.36 ± 0.35 0.035 * Perirenal fat (mm) 4.63 ± 0.25 3.27 ± 0.29 0.004 * Greater omentum (mm) 3.11 ± 0.22 1.98 ± 0.30 0.006 * * : P < 0.05 Table 3 Comparison of serological indices of model and control rats Model rats (n = 3) Control rats (n = 3) P-value ALT (IU/L) 117.89 ± 2.35 33.36 ± 0.62 < 0.001 * AST (IU/L) 84.06 ± 0.86 28.61 ± 1.08 < 0.001 * TC (mmol/L) 20.51 ± 0.08 6.37 ± 0.10 < 0.001 * TG (mmol/L) 8.25 ± 0.05 2.54 ± 0.04 < 0.001 * HDL-C (mmol/L) 1.27 ± 0.01 2.89 ± 0.18 < 0.001 * LDL-C (mmol/L) 6.96 ± 0.08 2.93 ± 0.09 < 0.001 * E2 (ng/L) 13.36 ± 0.22 5.19 ± 0.17 < 0.001 * T (ng/mL) 0.53 ± 0.02 1.24 ± 0.01 < 0.001 * IGF-1 (µg/L) 9.58 ± 0.23 5.14 ± 0.11 < 0.001 * * : P < 0.05 ALT, alanine transaminase; AST, aspartate aminotransferase; TC, total cholesterol; TG, triglycerides; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; E2, estrogen; T, testosterone; IGF-1, insulin-like growth factor 1. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5302221","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":368811912,"identity":"1657419e-2472-46a3-8b74-9bfaf8311d74","order_by":0,"name":"Shujuan Guo","email":"","orcid":"","institution":"Liaocheng People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shujuan","middleName":"","lastName":"Guo","suffix":""},{"id":368811913,"identity":"9220a3d3-f6c9-4623-a7fd-fe3a60af2c8c","order_by":1,"name":"Guimei Li","email":"","orcid":"","institution":"Shandong Provincial Hospital Affiliated to Shandong First Medical University","correspondingAuthor":false,"prefix":"","firstName":"Guimei","middleName":"","lastName":"Li","suffix":""},{"id":368811914,"identity":"7ef1917f-4424-4034-aafd-5bc21d8ca1d6","order_by":2,"name":"Juan Zheng","email":"data:image/png;base64,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","orcid":"","institution":"Liaocheng People's Hospital","correspondingAuthor":true,"prefix":"","firstName":"Juan","middleName":"","lastName":"Zheng","suffix":""}],"badges":[],"createdAt":"2024-10-21 07:53:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5302221/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5302221/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":67907974,"identity":"156e5422-6551-4ea8-9f2c-29922f2f6e2d","added_by":"auto","created_at":"2024-10-31 03:53:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":11607766,"visible":true,"origin":"","legend":"\u003cp\u003eH\u0026amp;E staining of the liver of 7-week-old rats.\u003c/p\u003e\n\u003cp\u003e(A) control group; (B) model group. Scale bar=400 μm.\u003c/p\u003e","description":"","filename":"fig1.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/d60e81478ef604bcfb790cf6.png"},{"id":67908296,"identity":"8ba1babb-1c2b-46c4-bac4-71f2fda701d1","added_by":"auto","created_at":"2024-10-31 04:01:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":12009397,"visible":true,"origin":"","legend":"\u003cp\u003eH\u0026amp;E staining of the testis of 7-week-old rats.\u003c/p\u003e\n\u003cp\u003e(A) control group; (B) model group. Scale bar=100 μm.\u003c/p\u003e","description":"","filename":"fig2.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/017d7930c912004cb956e546.png"},{"id":67907394,"identity":"9e6b5887-96f7-4866-9009-59f45c660bd9","added_by":"auto","created_at":"2024-10-31 03:45:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":10209850,"visible":true,"origin":"","legend":"\u003cp\u003eOil red O staining of the liver of 7-week-old rats.\u003c/p\u003e\n\u003cp\u003e(A) control group; (B) model group. Scale bar=400 μm.\u003c/p\u003e","description":"","filename":"fig3.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/cb6c2d0ff484627d1bf75716.png"},{"id":67907398,"identity":"d4a8128f-7d93-4da5-8b12-9856912008e0","added_by":"auto","created_at":"2024-10-31 03:45:26","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":11403028,"visible":true,"origin":"","legend":"\u003cp\u003eExpression of aromatase in the liver of 7-week-old rats.\u003c/p\u003e","description":"","filename":"fig4.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/d759ecfad3a7bfc009c39f0b.png"},{"id":67907392,"identity":"3e8eff67-a497-4cdf-b1db-93afe43d3110","added_by":"auto","created_at":"2024-10-31 03:45:25","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1794836,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of optical density of aromatase-positive staining in the liver.\u003c/p\u003e\n\u003cp\u003e(A) control group; (B) model group. Scale bar=400 μm.\u003c/p\u003e","description":"","filename":"fig5.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/a6d135ae64e3a07992f65c2e.png"},{"id":67907395,"identity":"967ad47d-0c03-41ae-9c25-2388234e2103","added_by":"auto","created_at":"2024-10-31 03:45:26","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":10255582,"visible":true,"origin":"","legend":"\u003cp\u003eExpression of aromatase in the testis of 7-week-old rats.\u003c/p\u003e\n\u003cp\u003e(A) control group; (B) Model group. Scale bar=100 μm.\u003c/p\u003e","description":"","filename":"fig6.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/3ba48e9291ef9d83d0f10aa4.png"},{"id":67907970,"identity":"b841628c-470f-493d-b257-24c33de0ab6d","added_by":"auto","created_at":"2024-10-31 03:53:25","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":1034897,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of optical density of aromatase-positive staining in the testis.\u003c/p\u003e","description":"","filename":"fig7.tif.png","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/57dbc1d7f32660a8ba19679c.png"},{"id":68094868,"identity":"8181b5d0-2292-47fc-a227-3f71870aeba4","added_by":"auto","created_at":"2024-11-02 20:31:47","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":53797115,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5302221/v1/9095a478-b983-4666-80b9-54daf4290dd6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effects of high-fat diet-induced obesity on metabolism and sexual development of juvenile male rats","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eChildhood obesity has become a global epidemic \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Its occurrence is influenced by several factors, among which changes in dietary structure, such as high-fat diets, greatly increase the risk of obesity. A high-fat diet increases the accumulation of lipids, inducing hyperlipidemia. Hyperlipidemia plays an essential role in metabolic diseases, leading to hepatic steatosis, Type 2 diabetes, and atherosclerosis \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. It also affects the functions of the hypothalamo-pituitary-gonadal axis, such as reducing testosterone (T) levels and increasing the risk of functional hypogonadism \u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. The influence of obesity on the reproductive system of male adults has been widely studied. However, some childhood obesity may persist into adulthood. Therefore, adult obesity is closely related to pubertal obesity, further highlighting the importance of studying the impact of pubertal obesity on the body.\u003c/p\u003e \u003cp\u003eThe correlation between boy obesity and the onset of adolescence in boys remains controversial. A multicenter epidemiological survey in China analyzed 9812 6-18-year-old boys and found that obesity was significantly positively correlated with sexual maturity \u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e, consistent with other previous studies \u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. Crocker \u003cem\u003eet al.\u003c/em\u003e reported a negative correlation between the degree of obesity in boys and testicular volume and pubic hair development. This might be related to the increased expression of aromatase in adipose tissue, promoting the conversion of T to estrogen (E2) and the occurrence of insulin resistance \u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Oehme \u003cem\u003eet al.\u003c/em\u003e conducted cross-sectional studies and found that boys with low body mass index (BMI) exhibited delayed sexual development, while boys with high BMI had similar sexual development time as boys with normal weight \u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. The inconsistency in these studies may be related to differences in the selection of indicators or the study population.\u003c/p\u003e \u003cp\u003eHerein, a pubertal obesity rat model was constructed by administering a high-fat diet before sexual maturation to explore the effects of obesity on metabolism and sexual development.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003etwenty-two specific-pathogen-free Sprague Dawley (SD) male rats (3 weeks old, weighing 50\u0026ndash;55 g) were maintained at a room temperature of 23\u0026ndash;25℃ and on a 12/12-h light/dark cycle, with \u003cem\u003ead libitum\u003c/em\u003e access to drinking water and food.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Grouping and feeding\u003c/h2\u003e \u003cp\u003eThe rats were randomly divided into the normal diet group and the high-fat diet group. The normal diet group received a regular diet as the control group (11 rats). The high-fat diet group received a high-fat and high-calorie diet as the model group (11 rats). All rats were raised until 7 weeks of age.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Indicators\u003c/h2\u003e \u003cp\u003eFood and water were withdrawn 6 h before measurement. Body length (distance from nose tip to anus), BMI, waist circumference, penis length, and testicular size were measured. Lee\u0026rsquo;s index was calculated as follows: Lee\u0026rsquo;s index = (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\sqrt[3]{\\text{w}\\text{e}\\text{i}\\text{g}\\text{h}\\text{t}\\:}\\times\\:1000\\)\u003c/span\u003e\u003c/span\u003e/body length (cm)) \u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eCriteria for successful modeling: Lee\u0026rsquo;s index of the model rat exceeded the upper limit of Lee\u0026rsquo;s index of the control group (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Reagents\u003c/h2\u003e \u003cp\u003e(1) Polyformaldehyde (Shanghai Sangon, China); (2) phosphate-buffered saline (PBS) powder (Zhongshan, China); (3) absolute alcohol (Sinopharm, China); (4) hematoxylin stain (Nanjing Jiangcheng, China); (5) eosin solution (Beyotime, China); (6) neutral resin (Sinopharm, China); (7) primary cytochrome P450 antibody (rabbit-derived) (Zen-bioscience, China); and (8) horseradish peroxidase-labeled secondary antibody (goat anti-rabbit) (Abcam, USA).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Methods\u003c/h2\u003e \u003cp\u003eAfter anesthetizing rats with 7% chloral hydrate (0.5 mL/100 g), approximately 10 mL of blood was collected from the abdominal aorta and transferred to a pro-coagulant tube. The blood was left to settle for 2 h and then the serum was stored at -20℃. The levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT), aspartate transaminase (AST), T, E2, and insulin-like growth factor 1 (IGF-1) were detected.\u003c/p\u003e \u003cp\u003eAfter blood collection, hepatic and testicular tissues were collected separately, and residual blood was washed with PBS. Samples were fixed with 4% paraformaldehyde for hematoxylin and eosin (H\u0026amp;E) staining and immunohistochemical detection. Some hepatic tissues were made into frozen sections and used for Oil Red O staining to observe hepatic steatosis.\u003c/p\u003e \u003cp\u003eTissues were dehydrated, cleared, embedded in paraffin, and sliced (thickness\u0026thinsp;=\u0026thinsp;5 \u0026micro;m). Sections were deparaffinized for further H\u0026amp;E staining. Morphological changes of the liver and testicles were observed under an optical microscope. Sections were dewaxed, antigen retrieved, blocked with goat serum, and incubated with a primary aromatase antibody (dilution ratio\u0026thinsp;=\u0026thinsp;1:100) at 4℃ overnight. Sections were incubated with a goat anti-rabbit secondary antibody (dilution ratio\u0026thinsp;=\u0026thinsp;1:50) at 37℃ for 30 min. After color development with diaminobenzidine, sections were counterstained with hematoxylin for 5 min, and expression changes of aromatase were observed under an optical microscope. Pale yellow indicates positive expression.The degree of hepatic steatosis was observed after staining, counterstaining and sealing of frozen sections, and the lipid droplets were orange.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Statistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using SPSS 23.0 software, and data were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD. Two independent sample t-tests were used to compare normally distributed data, and a non-parametric test was used for comparison of non-normally distributed data. \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01 was considered highly statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Analysis of body surface indicators\u003c/h2\u003e \u003cp\u003eRats were raised to 7 weeks of age for comparative analysis. The results showed that the weight, waist-to-height ratio and Lee\u0026rsquo;s index were significantly higher and penis length was significantly lower in the model group than in the control group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). No significant differences in testicular volume of rats were found between the two groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Measurement of the fat pad and testicle\u003c/h2\u003e \u003cp\u003eThree rats were randomly selected from each group for fat pad and testicular measurements. The results showed that visceral fat weight, fat thickness of epididymis, perirenal area, and the greater omentum were significantly increased in the model group had compared with the control group, with statistically significant differences (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). However, no statistically significant differences in testicular weight of rats were found between the two groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Serum biochemical indicators\u003c/h2\u003e \u003cp\u003eALT, AST, TC, TG, LDL-C, E2, and IGF-1 levels increased significantly and HDL-C and T levels decreased drastically in the model group compared with the control group, with statistically significant differences (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.4 H\u0026amp;E staining of liver cells and testicles\u003c/h2\u003e \u003cp\u003eLiver cells had normal morphology and regular arrangement, and the nucleus was located in the center of the cell in control group rats. However, liver cells showed fat vacuoles that squeezed the nucleus in model group rats, resulting in varying degrees of steatosis. Additionally, the control group exhibited a regular arrangement of spermatogenic cells at all levels in the seminiferous tubules, with a complete and clear structure. However, intercellular connections in the upper layer of the seminiferous tubules were loose and the number of spermatogenic cells decreased in the model group.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Oil Red O staining of liver cells\u003c/h2\u003e \u003cp\u003eThe cytoplasm of liver cells appeared light blue, and the nucleus appeared dark blue in the control group, with a small amount of lipid droplets (red particulates). The model group showed a significant increase in lipid droplets in liver cells, with a red cytoplasm.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Immunohistochemical detection of aromatases in hepatic and testicular tissues\u003c/h2\u003e \u003cp\u003eAccumulative and average optical densities of aromatases increased significantly in the hepatic cells of rats in the model group compared with those in the control group, with statistically significant differences (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Moreover, accumulative and average optical densities of aromatases increased markedly in the testicular cells of rats in the model group compared with those in the control group, with statistically significant differences (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eAfter excessive intake of high-calorie foods, adipocytes store excess glucose and fat as TGs \u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e, with limitation. After reaching a critical level, the body will contribute to fat production by increasing the number of adipocytes \u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Hyperplasia of abdominal adipose tissues leads to abdominal obesity due to high-fat production activity in the mesenteric adipose tissues \u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. At the end of feeding, Lee\u0026rsquo;s index increased significantly in the model group compared with the control group, and the total fat content in the epididymis, perirenal area, and greater omentum was significantly higher in the model group than in the control group, confirming the above viewpoint. The waist-to-height ratio, an important index to evaluate abdominal obesity \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e, provided guiding significance in predicting risk factors for cardiovascular diseases \u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. Clinically, hypertriglyceridemia, low HDL-C, and high LDL-C, termed \u0026ldquo;atherogenic lipid triad\u0026rdquo; \u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e, have been considered the main risk factors for cardiovascular diseases. Our data demonstrated that the waist-to-height ratio increased significantly in the model group compared with the control group. Moreover, TC, TG, and LDL-C levels were significantly higher and the HDL-C level was lower in the model group than in the control group, consistent with the research results of obesity-induced dyslipidemia in humans \u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eUnder a high-fat diet, adipocytes continuously break down to produce a large amount of free fatty acids and enhance the activity of lipoprotein lipase, leading to dyslipidemia and non-alcoholic fatty liver diseases \u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. Meanwhile, H\u0026amp;E staining revealed that the arrangement of liver cells in the model group was disordered during this period, with some rats developing steatosis. Oil Red O staining showed a significant increase in lipid droplets in liver cells. Lipid metabolism disorder and the increased synthesis and decreased oxidation of free fatty acids led to the accumulation of lipids and lipoproteins in cells, causing liver cell dysfunction \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. Additionally, ALT and AST levels were significantly higher in the model group than in the control group.\u003c/p\u003e \u003cp\u003eCurrently, there is no uniform conclusion on the relationship between obesity and the onset of sexual development in boys. Lee \u003cem\u003eet al.\u003c/em\u003e found that obese boys had delayed adolescence compared with normal and overweight boys based on a large-scale American population (3872 boys) \u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e. Holmgren \u003cem\u003eet al.\u003c/em\u003e defined adolescent development as the increase in height during adolescence and found that the adolescence of overweight and obese boys started 2.5\u0026ndash;3.5 months earlier than normal-weight children \u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. A different study reported that obese children had increased insulin sensitivity and levels of gonadotropins (follicle-stimulating hormone and luteinizing hormone (LH)) and sex hormone-binding globulin (SHBG) after weight loss, suggesting that obesity had negative influences on the sexual development of boys \u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. The present study found that prepubertal obesity first affected the penis length of rats, which was significantly shorter than that of the control group. Although status changes in testicular tissues were observed under light microscopy, testicular volume and mass were not significantly affected.\u003c/p\u003e \u003cp\u003eExcess accumulation of adipose tissues in the body enhanced aromatase activity, promoting the conversion of T into E2 \u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Increased E2 levels further inhibited the function of the hypothalamus (gonadotropin-releasing hormone)-pituitary (LH)-testicular (Leydig cells) axis. Moreover, E2 can further reduce T synthesis by inhibiting 17a-hydroxylase activity \u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e. Additionally, obesity can lead to insulin resistance, and insulin can inhibit the production of androgen and increase its clearance rate in the liver \u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e, resulting in decreased serum levels of T. The current study found that the level of aromatase in the liver and testicular tissues increased in the model group compared with the control group. In addition, the level of E2 increased significantly and that of T decreased substantially in the model group compared with the control group, ultimately affecting the development of the penis. IGF-1, a polypeptide hormone composed of 70 amino acids, is mainly produced in the liver. It is also stimulated by growth hormones and insulin endocrine in the liver \u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIGF-1 is closely related to various metabolic diseases, including obesity, Type 2 diabetes, and cardiovascular diseases \u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e. Our study showed that the level of IGF-1 was significantly higher in the model than in the control group, which is related to the regulation of the stability and biological activity of IGF-1 by insulin-like growth factor binding protein-1 (IGFBP-1) produced by the liver and insulin regulation. Adipose tissue, an endocrine organ, is closely related to insulin sensitivity. The accumulation of visceral fat leads to increased production of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-alpha, and IL-8, which reduces insulin sensitivity and results in hyperinsulinemia and even insulin resistance \u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e. However, we did not detect the insulin level but we speculate that insulin levels in the model group are elevated. Hyperinsulinemia not only reduces IGFBP-1 levels \u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e but also directly stimulates the production of IGF-1. Low levels of IGFBP-1 can promote IGF-1 activity \u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e, ultimately leading to increased IGF-1 secretion. Elevated IGF-1 levels also indicate the occurrence of metabolic disorders in rats.\u003c/p\u003e \u003cp\u003eIn summary, the sexual maturation of SD rats is approximately 6\u0026ndash;10 weeks after birth \u003csup\u003e[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e. We constructed a pubertal rat model of high-fat diet-induced obesity (7 weeks) to investigate the effects of prepubertal obesity on metabolism and sexual development. The findings demonstrated that a high-fat diet led to obesity, and the dyslipidemia induced by obesity not only affected the metabolic function of the liver but also damaged the reproductive system of male rats. Therefore, for children with prepubertal obesity, early dietary and weight management is essential to avoid the consequences of obesity.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eEthics approval and consent to participate\u003c/h2\u003e \u003cp\u003e This study was approved by the Ethics Committee of Liaocheng People\u0026rsquo;s Hospital.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eAll authors approved the final manuscript and the submission to this journal.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompeting interests\u003c/strong\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eNo funding was supported in this study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConceptualization: Guimei Li.Data curation: Shujuan Guo.Formal analysis:Juan Zheng.Investigation: Shujuan Guo.Methodology:Juan Zheng.Project administration: Juan Zheng.Resources: Guimei Li.Software: Shujuan Guo.Supervision: Guimei Li.Validation: Juan Zheng.Visualization: Shujuan Guo.Writing \u0026ndash; original draft: Shujuan Guo.Writing \u0026ndash; review \u0026amp; editing: Juan Zheng.All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eWe would like to thank the study participants for their time.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eThe datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWang Y, Lobstein T. Worldwide trends in childhood overweight and obesity. Int J Pediatr Obes, 2006;1(1):11\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDos Santos GF, Veras ASC, de Freitas MC,et al. Strength traning reduces lipid accumulation in liver of obese Wistar rats. Life Sciences, 235(2019)116834.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGhaderpour S, Ghiasi R, Heydari H, et al. The relation between obesity, kisspeptin, leptin, and male fertility. Horm Mol Biol Clin Investing, 2021,43(2):235\u0026ndash;247.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRosario Pivonello, Davide Menafra,Enrico Riccio,et al. Metabolic Disorders and Male Hypogonadotropic Hypogonadism. Frontiers in Endocrinology, July 2019, Volume 10,Ariticle 345.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDai YL, Fu JF, Liang L, et al. Association between obesity and sexual maturation in Chinese children: a muticenter study. Int J Obes (Lond), 2014,38(10):1312\u0026ndash;1316.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTomova A, Robeva R, Kumanov P. Influence of the body weight on the onset and progression of puberty in boys. J Pediatr Endocrinol Metab, 2015, 28(7\u0026ndash;8):859\u0026ndash;865.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCrocker MK, Stern EA, Sedaka NM, et al. Sexual dimorphisms in the associations of BMI and body fat with indices of pubertal development in girls and boys. J Clin Endocrinol Metab, 2014,99(8):E1519-1529.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOehme N, Roelants M, Bruserud IS, et al. Low BMI, but not high BMI, influences the timing of puberty in boys. Andrology, 2021, 9(3):837\u0026ndash;845.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBemardis LL, Patterson BD. Correlation between \u0026ldquo;Lee index\u0026rdquo; and carcass fat content in weanling and adult female rats with hypothalamic lesions. J Endoefinol, 1968,40(4):527\u0026ndash;528.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTarantino G,Savastano S,Colao A,et al. Hepatic steatosis,low-grade chronic inflammation and hormone /growth factor /adipokine imbalance. World J Gastroenterol, 2010,16(38): 4773\u0026ndash;4783.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarques BG, Hausman DB, Martin RJ. Association of fat cell size and paracrine growth factors in development of hyperplastic obesity. Am J Physiol, 1998; 275: R1898- R1908.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDhawan D, Sharma S. Abdominal obesity, adipokines and non-communicable diseases. J Steroid Biochem Mol Biol, 2020,203:105737.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrowning LM, Hsieh SD, et al. A systematic review of waist-to-height ratio as a screening tool for the prediction of cardiovascular disease and diabetes: 0.5could be a suitable global boundary value. Nutr Res Rev,2010,23(2):247\u0026ndash;269.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCai L, Liu A, Zhang Y, et al. Waist-to-height ratio and cardiovascular risk factors among Chinese adults in Beijing. PLoS One, 2013,8(7):e69298.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTchernof A, Desprrs JP. Pathophysiology of human visceral obesity: an update. Physiol Rev, 2013,93(1):359\u0026ndash;404.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSR Daniels. Department of Pediatrics, University of Colorado School of Medicine, and The Children\u0026rsquo;s Hospital, Denver, CO, USA. Complications of obesity in children and adolescents. International Journal of Obesity, (2009)33,S60-S65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeng L, Luo N, Mi J. Impacts of types and degree of obesity on non-alcoholic fatty liver disease and related dyslipidemia in Chinese school-age children. Biomed Environ Sci, 2011,24(1):22\u0026ndash;30.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEdward Nehus, Mark Mitsne. Childhood Obesity and the Metabolic Syndrome. Pediatr Clin N Am, 66(2019)31\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee JM, Wasserman R, Kaciroti N, et al. Timing of Puberty in Overweight Versus Obese Boys. Pediatrics, 2016;137:e20150164.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHolmgren A, Niklasson A, Nierop AF, et al. Pubertal height gain is inversely related to peak BMI in childhood. Pediatr. Res, 2017;81:448\u0026ndash;454.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBirkebaek NH, Lange A,Holland-Fischer P, et a1. Effect of weight reduction on insulin sensitivity, sex hormone-binding globulin,sex hormones and gonadotrophins in obese children. Eur J Endoerinol, 2010,163(6):895\u0026ndash;900.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZumoff B: Hormonal abnormalities in obesity. Acta Med Stand Suppl 1988, 723:153\u0026ndash;160.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGreenman Y, Tordjman K, Stem N, et al. Increased body weight associated prolactin secreting pituitary adenomas:weight loss with normalization of prolactin levels. Clin Endocrinol Metab, 1998,48(4):547\u0026ndash;553.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePasquali R, Casimirri F, Cantobelli S, et al. Effect of obesity and body fat distribution on sex hormone and insulin in man. Mtaholism, 1991,40:101\u0026ndash;104.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAguirre GA, De Ita JR, de la Garza RG, et al. Insulin-like\u0026ensp; growth \u0026ensp;factor-1 \u0026ensp;deficiency and metabolic syndrome. J Transl Med, 2016; 14: 3.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen L, Chen Q, Xie B, et al. Disruption of the AMPK-TBC1D1 nexus increases lipogenic gene expression and causes obesity in mice via promoting IGF1 secretion. Proc Natl Acad Sci USA, 2016,113(26):7219\u0026ndash;7224.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHigashi Y, Gautam S, Delafontaine P, et al. IGF-1 and cardiovascular disease. Growth Horm IGF Res, 2019;45:6\u0026ndash;16.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhmed B, Sultana R, Greene MW. Adipose tissue and insulin resistance in obese. Biomed Pharmacother, 2021;137:111315.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCaputo M, Pigni S, Agosti E, et al. Regulation of GH and GH Signaling by Nutrients. Cells, 2021,10(6):1376.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLeRoith D, Holly JMP, Forbes BE. Insulin-like growth factors: Ligands, binding proteins, and receptors. Mol Metab, 2021,52:101245.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMiao Mingsan. Experimental animals and animal experimental techniques. Beijing: China Traditional Chinese Medicine Press, 1997, 97.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eComparison of physical parameters of model and control rats\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eModel rats (n\u0026thinsp;=\u0026thinsp;11)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eControl rats (n\u0026thinsp;=\u0026thinsp;11)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eP-value\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eBody weight (g)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e193.96\u0026thinsp;\u0026plusmn;\u0026thinsp;18.07\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e177.78\u0026thinsp;\u0026plusmn;\u0026thinsp;11.91\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.022\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eW/H\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eLee\u0026rsquo;s index\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e312.73\u0026thinsp;\u0026plusmn;\u0026thinsp;5.20\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e280.87\u0026thinsp;\u0026plusmn;\u0026thinsp;5.40\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003ePenis length (mm)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e9.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e11.06\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eTesticular volume (cm\u003csup\u003e3\u003c/sup\u003e)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.86\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.075\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003e*: \u003cspan class=\"Italic\"\u003eP\u003c/span\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003eW/H: ratio of waist circumference to body length\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eComparison of visceral fat and testis of model and control rats\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eModel rats (n\u0026thinsp;=\u0026thinsp;3)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eControl rats (n\u0026thinsp;=\u0026thinsp;3)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eP-value\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eVisceral fat (g)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4.95\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.022\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eTesticular weight (g)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.105\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eEpididymal fat (mm)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.44\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.035\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003ePerirenal fat (mm)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.004\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGreater omentum (mm)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.98\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.006\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003e\u003csup\u003e*\u003c/sup\u003e: \u003cspan class=\"Italic\"\u003eP\u003c/span\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eComparison of serological indices of model and control rats\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eModel rats (n\u0026thinsp;=\u0026thinsp;3)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eControl rats (n\u0026thinsp;=\u0026thinsp;3)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eP-value\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eALT (IU/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e117.89\u0026thinsp;\u0026plusmn;\u0026thinsp;2.35\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e33.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.62\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eAST (IU/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e84.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.86\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e28.61\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eTC (mmol/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e20.51\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e6.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eTG (mmol/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e8.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eHDL-C (mmol/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.89\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eLDL-C (mmol/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e6.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eE2 (ng/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e13.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e5.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eT (ng/mL)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.53\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.24\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eIGF-1 (\u0026micro;g/L)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e9.58\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e5.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003e\u003csup\u003e*\u003c/sup\u003e: \u003cspan class=\"Italic\"\u003eP\u003c/span\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003eALT, alanine transaminase; AST, aspartate aminotransferase; TC, total cholesterol; TG, triglycerides; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; E2, estrogen; T, testosterone; IGF-1, insulin-like growth factor 1.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"high-fat diet, lipid metabolism, liver, testis, sex hormones","lastPublishedDoi":"10.21203/rs.3.rs-5302221/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5302221/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo explore the effects of high-fat diet-induced obesity on the metabolism and sexual development of juvenile male rats.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThree-week-old male rats were divided into the control group and the model group. The two groups were fed normal and high-fat diets, respectively, for four weeks. Modeling was successful if Lee\u0026rsquo;s index exceeded the upper limit of Lee\u0026rsquo;s index of the control group. Levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT), aspartate transaminase (AST), testosterone (T), estrogen (E2), and insulin-like growth factor 1 (IGF-1) of the rats were monitored. Morphological structures of hepatic and testicular tissues were examined by hematoxylin and eosin (H\u0026amp;E) staining; hepatic steatosis was investigated by Oil Red O staining; and aromatases were detected using the immunohistochemical method.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eWeight, waist-to-height ratio, Lee\u0026rsquo;s index, weight and thickness of visceral fat, levels of ALT, AST, TC, TG, LDL-C, E2, and IGF-1 of rats were significantly higher in the model group than in the control group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). H\u0026amp;E staining revealed that rats in the model group had hepatic steatosis, a disorder of seminiferous tubules, and a reduced quantity of spermatogenic cells. Oil Red O staining revealed a significantly increased accumulation of lipid droplets in hepatic cells. Immunohistochemical analysis revealed that aromatases in hepatic and testicular cells were up-regulated.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eA high-fat diet induces dyslipidemia, thereby causing hepatic steatosis and liver dysfunction, and it significantly influences testicular development, as an increased level of aromatase leads to a reduced T level.\u003c/p\u003e","manuscriptTitle":"Effects of high-fat diet-induced obesity on metabolism and sexual development of juvenile male rats","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-10-31 03:45:21","doi":"10.21203/rs.3.rs-5302221/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d35e83fb-0856-4b66-a3a9-64d595b890d3","owner":[],"postedDate":"October 31st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-11-02T20:23:18+00:00","versionOfRecord":[],"versionCreatedAt":"2024-10-31 03:45:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5302221","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5302221","identity":"rs-5302221","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}